1
|
Schmitd LB, Hafner H, Ward A, Asghari Adib E, Biscola NP, Kohen R, Patel M, Williamson RE, Desai E, Bennett J, Saxman G, Athaiya M, Wilborn D, Shumpert J, Zhao XF, Kawaguchi R, Geschwind DH, Hoke A, Shrager P, Collins CA, Havton LA, Kalinski AL, Giger RJ. Sarm1 is not necessary for activation of neuron-intrinsic growth programs yet required for the Schwann cell repair response and peripheral nerve regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583374. [PMID: 38496662 PMCID: PMC10942360 DOI: 10.1101/2024.03.04.583374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Upon peripheral nervous system (PNS) injury, severed axons undergo rapid SARM1-dependent Wallerian degeneration (WD). In mammals, the role of SARM1 in PNS regeneration, however, is unknown. Here we demonstrate that Sarm1 is not required for axotomy induced activation of neuron-intrinsic growth programs and axonal growth into a nerve crush site. However, in the distal nerve, Sarm1 is necessary for the timely induction of the Schwann cell (SC) repair response, nerve inflammation, myelin clearance, and regeneration of sensory and motor axons. In Sarm1-/- mice, regenerated fibers exhibit reduced axon caliber, defective nerve conduction, and recovery of motor function is delayed. The growth hostile environment of Sarm1-/- distal nerve tissue was demonstrated by grafting of Sarm1-/- nerve into WT recipients. SC lineage tracing in injured WT and Sarm1-/- mice revealed morphological differences. In the Sarm1-/- distal nerve, the appearance of p75NTR+, c-Jun+ SCs is significantly delayed. Ex vivo, p75NTR and c-Jun upregulation in Sarm1-/- nerves can be rescued by pharmacological inhibition of ErbB kinase. Together, our studies show that Sarm1 is not necessary for the activation of neuron intrinsic growth programs but in the distal nerve is required for the orchestration of cellular programs that underlie rapid axon extension.
Collapse
Affiliation(s)
- Ligia B. Schmitd
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Hannah Hafner
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Ayobami Ward
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor MI, USA
| | - Elham Asghari Adib
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Natalia P. Biscola
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rafi Kohen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Manav Patel
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Emily Desai
- Department of Biology, Ball State University, Muncie IN, USA
| | | | - Grace Saxman
- Department of Biology, Ball State University, Muncie IN, USA
| | - Mitre Athaiya
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - David Wilborn
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Jaisha Shumpert
- Department of Biology, Ball State University, Muncie IN, USA
| | - Xiao-Feng Zhao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
| | - Riki Kawaguchi
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Daniel H. Geschwind
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Institute of Precision Health, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ahmet Hoke
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA
| | - Peter Shrager
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Catherine A. Collins
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA
| | - Leif A. Havton
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J Peters VA Medical Center, Bronx, NY, USA
| | - Ashley L. Kalinski
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Biology, Ball State University, Muncie IN, USA
| | - Roman J. Giger
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor MI, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor MI, USA
| |
Collapse
|
2
|
Bartmeyer PM, Biscola NP, Havton LA. Nonbinary 2D Distribution Tool Maps Autonomic Nerve Fiber Clustering in Lumbosacral Ventral Roots of Rhesus Macaques. eNeuro 2024; 11:ENEURO.0009-23.2024. [PMID: 38548331 PMCID: PMC11015947 DOI: 10.1523/eneuro.0009-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 12/13/2023] [Accepted: 02/05/2024] [Indexed: 04/14/2024] Open
Abstract
Neuromodulation of the peripheral nervous system (PNS) by electrical stimulation may augment autonomic function after injury or in neurodegenerative disorders. Nerve fiber size, myelination, and distance between individual fibers and the stimulation electrode may influence response thresholds to electrical stimulation. However, information on the spatial distribution of nerve fibers within the PNS is sparse. We developed a new two-dimensional (2D) morphological mapping tool to assess spatial heterogeneity and clustering of nerve fibers. The L6-S3 ventral roots (VRs) in rhesus macaques were used as a model system to map preganglionic parasympathetic, γ-motor, and α-motor fibers. Random and ground truth distributions of nerve fiber centroids were determined for each VR by light microscopy. The proposed tool allows for nonbinary determinations of fiber heterogeneity by defining the minimum distance between nerve fibers for cluster inclusion and comparisons with random fiber distributions for each VR. There was extensive variability in the relative composition of nerve fiber types and degree of 2D fiber heterogeneity between different L6-S3 VR levels within and across different animals. There was a positive correlation between the proportion of autonomic fibers and the degree of nerve fiber clustering. Nerve fiber cluster heterogeneity between VRs may contribute to varied functional outcomes from neuromodulation.
Collapse
Affiliation(s)
- Petra M Bartmeyer
- Departments of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Natalia P Biscola
- Departments of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Leif A Havton
- Departments of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10029
- James J. Peters Veterans Affairs Medical Center, Bronx, New York 10468
| |
Collapse
|
3
|
Peña E, Pelot NA, Grill WM. Computational models of compound nerve action potentials: Efficient filter-based methods to quantify effects of tissue conductivities, conduction distance, and nerve fiber parameters. PLoS Comput Biol 2024; 20:e1011833. [PMID: 38427699 PMCID: PMC10936855 DOI: 10.1371/journal.pcbi.1011833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 03/13/2024] [Accepted: 01/16/2024] [Indexed: 03/03/2024] Open
Abstract
BACKGROUND Peripheral nerve recordings can enhance the efficacy of neurostimulation therapies by providing a feedback signal to adjust stimulation settings for greater efficacy or reduced side effects. Computational models can accelerate the development of interfaces with high signal-to-noise ratio and selective recording. However, validation and tuning of model outputs against in vivo recordings remains computationally prohibitive due to the large number of fibers in a nerve. METHODS We designed and implemented highly efficient modeling methods for simulating electrically evoked compound nerve action potential (CNAP) signals. The method simulated a subset of fiber diameters present in the nerve using NEURON, interpolated action potential templates across fiber diameters, and filtered the templates with a weighting function derived from fiber-specific conduction velocity and electromagnetic reciprocity outputs of a volume conductor model. We applied the methods to simulate CNAPs from rat cervical vagus nerve. RESULTS Brute force simulation of a rat vagal CNAP with all 1,759 myelinated and 13,283 unmyelinated fibers in NEURON required 286 and 15,860 CPU hours, respectively, while filtering interpolated templates required 30 and 38 seconds on a desktop computer while maintaining accuracy. Modeled CNAP amplitude could vary by over two orders of magnitude depending on tissue conductivities and cuff opening within experimentally relevant ranges. Conduction distance and fiber diameter distribution also strongly influenced the modeled CNAP amplitude, shape, and latency. Modeled and in vivo signals had comparable shape, amplitude, and latency for myelinated fibers but not for unmyelinated fibers. CONCLUSIONS Highly efficient methods of modeling neural recordings quantified the large impact that tissue properties, conduction distance, and nerve fiber parameters have on CNAPs. These methods expand the computational accessibility of neural recording models, enable efficient model tuning for validation, and facilitate the design of novel recording interfaces for neurostimulation feedback and understanding physiological systems.
Collapse
Affiliation(s)
- Edgar Peña
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Neurosurgery, Duke University School of Medicine, Durham, North Carolina, United States of America
| |
Collapse
|
4
|
Havton LA, Biscola NP, Stern E, Mihaylov PV, Kubal CA, Wo JM, Gupta A, Baronowsky E, Ward MP, Jaffey DM, Powley TL. Human organ donor-derived vagus nerve biopsies allow for well-preserved ultrastructure and high-resolution mapping of myelinated and unmyelinated fibers. Sci Rep 2021; 11:23831. [PMID: 34903749 PMCID: PMC8668909 DOI: 10.1038/s41598-021-03248-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/15/2021] [Indexed: 11/09/2022] Open
Abstract
The vagus nerve provides motor, sensory, and autonomic innervation of multiple organs, and electrical vagus nerve stimulation (VNS) provides an adjunctive treatment option for e.g. medication-refractory epilepsy and treatment-resistant depression. The mechanisms of action for VNS are not known, and high-resolution anatomical mapping of the human vagus nerve is needed to better understand its functional organization. Electron microscopy (EM) is required for the detection of both myelinated and unmyelinated axons, but access to well-preserved human vagus nerves for ultrastructural studies is sparse. Intact human vagus nerve samples were procured intra-operatively from deceased organ donors, and tissues were immediately immersion fixed and processed for EM. Ultrastructural studies of cervical and sub-diaphragmatic vagus nerve segments showed excellent preservation of the lamellated wall of myelin sheaths, and the axolemma of myelinated and unmyelinated fibers were intact. Microtubules, neurofilaments, and mitochondria were readily identified in the axoplasm, and the ultrastructural integrity of Schwann cell nuclei, Remak bundles, and basal lamina was also well preserved. Digital segmentation of myelinated and unmyelinated axons allowed for determination of fiber size and myelination. We propose a novel source of human vagus nerve tissues for detailed ultrastructural studies and mapping to support efforts to refine neuromodulation strategies, including VNS.
Collapse
Affiliation(s)
- Leif A Havton
- Departments of Neurology and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY, USA.
| | - Natalia P Biscola
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Esther Stern
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Plamen V Mihaylov
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - John M Wo
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anita Gupta
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elizabeth Baronowsky
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| | - Matthew P Ward
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Deborah M Jaffey
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| | - Terry L Powley
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA
| |
Collapse
|
5
|
Eiber CD, Payne SC, Biscola NP, Havton LA, Keast JR, Osborne PB, Fallon JB. Computational modelling of nerve stimulation and recording with peripheral visceral neural interfaces. J Neural Eng 2021; 18. [PMID: 34740201 DOI: 10.1088/1741-2552/ac36e2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 11/05/2021] [Indexed: 12/30/2022]
Abstract
Objective.Neuromodulation of visceral nerves is being intensively studied for treating a wide range of conditions, but effective translation requires increasing the efficacy and predictability of neural interface performance. Here we use computational models of rat visceral nerve to predict how neuroanatomical variability could affect both electrical stimulation and recording with an experimental planar neural interface.Approach.We developed a hybrid computational pipeline,VisceralNerveEnsembleRecording andStimulation (ViNERS), to couple finite-element modelling of extracellular electrical fields with biophysical simulations of individual axons. Anatomical properties of fascicles and axons in rat pelvic and vagus nerves were measured or obtained from public datasets. To validate ViNERS, we simulated pelvic nerve stimulation and recording with an experimental four-electrode planar array.Main results.Axon diameters measured from pelvic nerve were used to model a population of myelinated and unmyelinated axons and simulate recordings of electrically evoked single-unit field potentials (SUFPs). Across visceral nerve fascicles of increasing size, our simulations predicted an increase in stimulation threshold and a decrease in SUFP amplitude. Simulated threshold changes were dominated by changes in perineurium thickness, which correlates with fascicle diameter. We also demonstrated that ViNERS could simulate recordings of electrically-evoked compound action potentials (ECAPs) that were qualitatively similar to pelvic nerve recording made with the array used for simulation.Significance.We introduce ViNERS as a new open-source computational tool for modelling large-scale stimulation and recording from visceral nerves. ViNERS predicts how neuroanatomical variation in rat pelvic nerve affects stimulation and recording with an experimental planar electrode array. We show ViNERS can simulate ECAPS that capture features of our recordings, but our results suggest the underlying NEURON models need to be further refined and specifically adapted to accurately simulate visceral nerve axons.
Collapse
Affiliation(s)
- Calvin D Eiber
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - Sophie C Payne
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, The University of Melbourne, Victoria, Australia
| | - Natalia P Biscola
- Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Leif A Havton
- Icahn School of Medicine at Mount Sinai, New York, United States of America
| | - Janet R Keast
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - Peregrine B Osborne
- Department of Anatomy and Physiology, The University of Melbourne, Victoria, Australia
| | - James B Fallon
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, The University of Melbourne, Victoria, Australia
| |
Collapse
|